feat(linkding): Add linkding stack

Bookmarking software similar to shaarli but a bit more featureful. And
not written in php, thankfully.

roles/linkding/handlers/main.yml

@@ -0,0 +1,52 @@
+## Register reverse proxy
+- name: Ensure upstream directory exists
+  ansible.builtin.file:
+    path: "{{ linkding_upstream_file_dir }}"
+    state: directory
+    mode: "0755"
+  become: true
+  listen: "update linkding upstream"
+
+- name: Update upstream template
+  ansible.builtin.template:
+    src: upstream.json.j2
+    dest: "{{ linkding_upstream_file_dir }}/upstream.json"
+  become: true
+  listen: "update linkding upstream"
+
+# figure out if upstream id exists
+- name: check {{ stack_name }} upstream
+  community.docker.docker_container_exec:
+    container: "{{ caddy_container_id }}"
+    command: >
+      curl localhost:2019/id/{{ stack_name }}_upstream/
+  changed_when: False
+  register: result
+  become: true
+  listen: "update linkding upstream"
+
+# upstream already exists, patch it
+- name: remove old {{ stack_name }} upstream
+  community.docker.docker_container_exec:
+    container: "{{ caddy_container_id }}"
+    command: >
+      curl -X DELETE localhost:2019/id/{{ stack_name }}_upstream/
+  become: true
+  when: (result.stdout | from_json)['error'] is not defined
+  listen: "update linkding upstream"
+
+# upstream has to be created
+- name: add {{ stack_name }} upstream
+  community.docker.docker_container_exec:
+    container: "{{ caddy_container_id }}"
+    command: >
+      curl -X POST -H "Content-Type: application/json" -d @{{ linkding_upstream_file_dir }}/upstream.json localhost:2019/config/apps/http/servers/{{ (linkding_use_https == True) | ternary(caddy_https_server_name, caddy_http_server_name) }}/routes/0/
+  become: true
+  listen: "update linkding upstream"
+
+- name: Ensure upstream directory is gone again
+  ansible.builtin.file:
+    path: "{{ linkding_upstream_file_dir }}"
+    state: absent
+  become: true
+  listen: "update linkding upstream"